"Part" identifiers

Is there a way of adding capital alpha-characters, enclosed in a circle, as seen in almost all folk music, identifying separate "parts". So in say a 32 bar piece, part A would be (usually) 16 bars, repeated, then move on to the B part of 16 bars, and repeat. So playing would be indicated in the header as AABB. If there are, say 3 parts, A,B and C, these would be identified at the appropriate point in the stave, and playing order shown in the header as. perhaps AABACA